Positive crankcase ventilation (PCV) circuits/systems and similar vacuum intake ports are in common use in gasoline burning internal combustion engines for automobiles in the United States and elsewhere. It is well known that the purpose and function of such systems is to collect blow-by from the engine crankcase and deliver it to the intake manifold under all but high-load/high-throttle setting conditions. In and of themselves, these systems do little or nothing to improve engine efficiency or fuel economy.
U.S. Pat. No. 7,117,859 discloses a system for metering fuel through a needle valve into fluid which is diverted from an automotive PCV circuit, and thoroughly vaporizing the fuel in one or more vaporization chambers before delivering the vaporized fuel/fluid mixture to the vehicle intake. It has been found that the end result of the use of this system is a surprising and significant increase in fuel economy.